[121] 
Austin Chalk Underlying Waco. 
7 
example, covering about 1 square mile around Speegleville | covering 
about 6 square miles of territory between Ross and Aquilla Stations, on 
the Texas Central Ry., and covering about 2 square miles around Bosque- 
ville. While it affords good grazing land and good farm lands, it is 
inferior to the Austin chalk. It is usually characterized by the growth 
of mesquite, but elm and red cedar are also found. Just after passing 
the fish pond (going west), on the Waco and Crawford road, the argilla- 
ceous limestone layers of the marl occur, inclined at an angle of 45 
degrees. The marl is seen around South Bosque Station in hills (which 
take the general form of the hills of the Austin chalk, but are more 
rounded) from 50 to 250 feet high. Potato Ridge is an isolated dome- 
shaped hill, 100 feet high, composed of this marl. 
A section of the Austin chalk and this marl, taken on the road just 
above South Bosque Station, gives the following: 
White limestone (or Austin chalk) 35 feet. 
Marl 125 feet. 
The best exposures of the marl seen in this county are around South 
Bosque Station. The marl is here seen covering an area -| to 1-J miles 
wide and extending north and south for a distance of 14 miles. In a 
bluff on South Bosque, -J mile above Milks crossing, the bands of the 
argillaceous limestone of this marl, above the Eagle Ford shale, are G 
to 8 inches, and sometimes more than a foot thick. These bands break 
up into large flags, some of which may be 7 by 8 feet across. The fossils 
found in this marl are distinct, but more closely resemble those of the 
Eagle Ford shale than those found in the Austin chalk. The most com- 
mon invertebrates found are Ostrea congesta, Conrad, and Inocerami. 
Austin chalk occurs in a small isolated area on the east bank of the 
Brazos river, above the mouth of the Bosque, but the main body (in 
this county) begins at the mouth of the Bosque, on the south side, and 
follows the line of the Bosque up to South Bosque Station ; thence south- 
east to within 2 miles of Loren a: thence through Ritchie to the southern 
part of Waco, about the mouth of Waco creek. This boundary on the 
south side is very hard to trace accurately on account of the almost 
imperceptible line of contact between the chalk and the Taylor or Pon- 
derosa marl. It requires close observation and collecting to distinguish 
between them. The towns of Lorena, Bruceville, and Eddy are on the 
Taylor marl, which covers a large area in the southern part of this 
county, extending also over a large part of Palls and Bell counties. 
From the description in this paper, and the sections given, it is seen 
that the marl spoken of by Prof. Hill a,s “the marl at the base of 
the Austin chalk” is of considerable importance. In the two well sec- 
tions and at Waco on Waco creek, the white limestone, or Austin chalk, 
lies directly upon the Eagle Ford shale, and there is no trace of this 
